The present invention relates to an aluminum alloy electric conductor wire, and more particularly to an aluminum alloy electric conductor wire which possesses high strength and excellent heat resistant properties.
Aluminum alloys which have heretofore been in general use for overhead transmission and distribution lines may be roughly divided into high strength aluminum alloys (Alloy 6201, Alloy 5005, "Aldrey"--trademark--Aluminum Alloy, etc.) and heat-resistant aluminum alloys. In the case of the former, the permissible service temperature is 90.degree. C. and their design standards are similar to those for the aluminum conductor steel reinforced (ACSR) conductors in general, while in the case of the latter, the service temperature is as high as 150.degree. C. and the alloys of this type are widely used for electric conductors for large capacity overhead transmission lines in recent times.
That is to say, the high strength aluminum alloys heretofore in general use have a characteristic feature of a high strength (for example, the tensile strength of Alloy 5005 which is an Al-Mg alloy is approximately 25 Kg/mm.sup.2 and that of "Aldrey" Aluminum Alloy, which is an Al-Mg-Si alloy, is 31.5 Kg/mm.sup.2), but their permissible temperatures are limited to a low point because of their properties, so that they have been unable to meet the need most keenly felt in recent years, i.e., the need for increasing power transmission capacity by raising the service temperature. On the other hand, the heat-resistant aluminum alloys are of ordinary aluminum for electrical purposes to which zirconium has been added in a quantity of about 0.1%. Their tensile strength is about equal to that of hard drawn aluminum used for electrical purposes. Generally, they are put in use with their low strength reinforced by compound stranding it with steel wires.
However, since demand for electrical power has increased remarkably in recent years, the necessity for developing techniques for large capacity transmission of electric power has become greater and greater, and the development of a new aluminum alloy for conductors which has satisfactory combined overall properties of strength, heat resistance and electrical conductivity has come to be desired.